Background: Pregnancy and childbirth alter pelvic floor anatomy and function. Over 4 million women give birth each year in the United States, and most experience genital tract trauma, including damage to the nerves and musculature of the pelvic floor. This trauma can cause short and long term problems for new mothers, including urinary and anal incontinence, sexual dysfunction, perineal pain, and pelvic floor anatomical changes. The prevalence and natural history of these disorders in healthy women is unknown. Specific Aims: The specific aims of this study are to 1) identify the prevalence of urinary and anal incontinence, sexual complaints, anatomical changes and perineal pain in women with and without genital tract trauma, prenatally and postpartum and to evaluate the effect of pelvic floor (PF) changes on maternal quality of life 2) compare PF changes in women with and without genital tract trauma 3) determine if modifiable second stage labor care measures are associatedwith PF changes and 4) compare PF changes in women who deliver by cesarean but do not enter the second stage of labor to women who deliver vaginally with and without genital tract trauma. Study population: Six hundred and thirty healthy nulliparous pregnant women cared for by nurse-midwives and 135 women who deliver by cesarean from the low risk obstetrical services in Albuquerque, New Mexico. Study Design: Prenatally, women will be recruited from three nurse midwifery clinics. Women will complete validated symptom severity scales and quality of life (QOL) questionnaires that measure PF function. Structured pelvic examinations incorporating the pelvic organ prolapse quantification system will evaluate pelvic floor anatomy. At birth, a detailed map of perineal trauma will be recorded. Women who deliver by cesarean will be recruited postpartum. At six weeks, six months and one year postpartum, women will complete symptom severity and QOL measures and undergo detailed pelvic exams. At 6 months, endoanal ultrasound to evaluate the anal sphincter, translabial 3 D ultrasonography to evaluate the levator ani and a paper towel test to document urinary incontinence will be performed. All women who deliver in the first three years of the study will be followed for the second year with symptom severity and QOL questionnaires. Significance of this work: Functional and anatomical disorders of the PF impact women's lives, and result in an economic burden to the health care system. Childbirth and pregnancy have been implicated as a cause of these disorders, yet the natural history of pelvic floor changes during pregnancy and following childbirth has yet to be described. This project will provide fundamental data to guide future decisions about labor interventions to prevent PF changes as well as data-based decisions regarding maternal request cesarean.